1. Field of the Invention
The present invention relates to a method for amplifying genomic DNA.
2. Description of the Related Art
A haplotype (haploid genotype) consists of structurally continuous genetic markers on an individual chromosome. In genetic association studies, haplotypes facilitate more precise mapping of the target gene within a chromosomal region identified by an initial linkage analysis with conventional genetic markers such as single-nucleotide polymorphisms (SNPs) and microsatellites. Assessing the haplotype is also important for further functional studies, because genetic markers on the same chromosome molecule may functionally interact with each other.
Despite the importance of haplotypes, the difficulty of their experimental determination, owing to the presence of two almost identical copies of chromosomes in diploid cells, has prevented their general use. Haplotypes spanning a long distance (usually more than tens of kilobase pairs) or consisting of many genetic markers are difficult to experimentally assess. Currently, most haplotypes are indirectly reconstructed by (1) statistical estimation from conventional genotype data or (2) inference from family data. The reliability of statistical estimation depends on various factors such as the number of genetic markers, population size, allele frequencies and linkage disequilibrium between the genetic markers. Inference from family data can be limited by the availability of DNA samples.
Recently, an increasing number of molecular haplotyping techniques have been proposed (Kwok, P.-Y & Xiao, M “Single-molecule analysis for molecular haplotyping.” Hum. Mut. 23, 442-446 (2004)). The polony approach (colony formation of target locus amplification products within a polyacrylamide gel by exogenously added Taq DNA polymerase, followed by in-gel sequential fluorescent single-base extension) has been successfully used for molecular haplotyping at the chromosome-wide level (Zhang, K. et al. “Long-range polony haplotyping of individual human chromosome molecules. Nat. Genet. 38, 382-387 (2006)).